President Volodymyr Zelensky’s dramatic October 8 message — “They need to be stopped completely; that would have a significant effect on energy-resource trade, and security in Europe as well” — underlined the reach and sophistication of Russia’s naval sanctions-busting equipment. Spying reported by Ukraine’s Foreign Intelligence Service depicts Moscow operating a clandestine shadow fleet of more than 500 tankers, shipping crude oil and petroleum products beyond the reach of global sanctions.
Russia’s shadow fleet, or “dark fleets” as they are sometimes referred to, consists mainly of aging vessels with an average 20-year age, compared to a 13-year global tanker average. There are numerous registered under flags of convenience that have a propensity to alter identity in service. Some work without legitimate insurance or on false documents, and some turn off their Automatic Identification System (AIS) transponders — a willful flouting of international maritime safety regulations. AIS, designed to send a vessel’s position, course, and speed, is of no use when disabled or spoofed, compounding detection and enforcement efforts.
The Boracay, captured in France on September 30, illustrates the act of persistent flag switching. Had been registered in a variety of jurisdictions and was showing no flag when French Navy commandos boarded it. Prosecutor Stéphane Kellenberger confirmed that the ship was headed for India with a heavy load of Russian crude from Primorsk. Under the United Nations Convention on the Law of the Sea, ships without nationality can be intercepted in international waters, but enforcement is premised on jurisdictional cooperation — problematically, when the trail of ownership creates secretive shell companies.
The contribution of the shadow fleet is not peripheral. French President Emmanuel Macron stated that “30 to 40 percent” of the effort of Russia at war is being financed by proceeds from these over €30 billion tankers. In August 2025, 53% of Russian oil exports travelled aboard G7+ tankers, down 8 percentage points from July, showing growing reliance on shadow ships. One quarter of the oil transported by shadow tankers that month had also been transported on vessels already under sanctions.
AIS spoofing is merely one aspect of disguise strategies. Satellite-imaging ship surveillance can track vessels even when AIS is disabled, through synthetic aperture radar (SAR), breaking clouds and darkness. Shadow fleet operators exploit coverage shortcomings and jurisdictional reluctance to act upon sightings outside territorial waters. Ship-to-ship (STS) deliveries valued at €121 million a day in EU waters last August further blur cargo origins, especially by uninsured or poorly inspected tankers.
Older vessels within the shadow fleet are severe environmental hazards. In the absence of adequate Protection & Indemnity (P&I) coverage, a spill would be more than €1 billion for coastal states in cleanup expenses. Greenpeace Ukraine’s Natalia Gozak warned that “lack of insurance added to the really old ships… increases the risk of environmental disaster.” The Baltic Sea, along which hundreds of shadow ships pass daily, is particularly vulnerable due to its narrow waters and delicate environment.
The EU, Australia, and Canada have expanded sanctions lists, targeting ships and intermediaries that facilitate shadow fleet operations. Canada’s most recent measures target more than 200 vessels. The EU’s 18th sanctions package prohibits imports of oil derived from Russian crude, closing a loophole allowing re-export from third countries. Enforcement remains uneven, however, with sanctioned vessels continuing to supply oil globally.
Analysts recommend cutting the price cap on oil to $30 a barrel, which would have cut 40% of Russian revenues since December 2022. Analysts also recommend banning STS transfers off G7+ waters, mandating transparent maritime insurance disclosure, and harmonizing vessel sanctions lists across jurisdictions. Maritime authorities can detain tankers under false colors or with no valid insurance and place them on OFAC, UK, and EU sanctions lists.
Integrating AIS data with SAR imagery and high-frequency radio direction finding would improve interdiction rates. Linking these datasets to port state control inspections would allow authorities to identify and detain suspected ships more efficiently. Baltic NATO navies are already monitoring shadow fleet movement, but operating reach is currently limited beyond national waters, requiring coordinated multinational patrols and intelligence sharing.
Russia’s shadow fleet’s survival is at once evidence of the ingenuity of sanctions circumvention and of the limitations of current enforcement measures. As Zelensky’s warning makes clear, elimination of this network is not merely an economic imperative but a strategic necessity for European security.